Pv=nRT... SIGH..........

A sample of O2 (g) has a volume of 26.7 L at 762 Torr. What is the new volume if, with
temperature and amount of gas held constant, the pressure is:
(a) lowered to 385 Torr

(b) increased to 3.68 atm

(a) P1V1 = P2V2
(26.7 L) (762 torr) = (V2) (385 torr)
V2 = 52.85 L

(b) P1V1 = P2V2
(26.7 L) (0.977 atm) = (V2) (3.68 atm)
V2 = 7.09 L

Why rate as best answer if you consider it to be wrong. Why is it wrong?

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Temperature and amount of gas are constant, and R is constant by definition. By simple algebra the ratios volumes is inversely proportional to the pressure (v1/v2 = p2/p1)

I don't have the conversion from torr to atmospheres memorized, so you'll need to look that up. However the first would be 26.7= (385/762) x v2

This isn't PV=nRT...It's P1V1=P2V2. Because temp is constant it is not included in the equation. Just submit your pressures and volumes into this (converting to atm and liters beforehand) to solve for V2, the volume after the pressure is changed.

Not a PV=nRT question (well, it could be) - you are really just looking at Boyle's Law P1V1 = P2V2 as the T and n are constant. In part B, just be sure to convert the pressure so they are both in the same units.